Water on Mars?

by Erin Kraal (Virginia Tech, USA)

In 2005, American director Steven Spielberg made a new version of this story, in which Tom Cruise fights aliens who try to destroy the Earth. See: http://www.waroftheworlds.com/

October 30, 1936, writer and film director Orson Welles hosted a radio show called War of the Worlds. The programme pretended to be a newsreel. It reported a Martian invasion of the Earth. The joke was a bit too funny. People actually believed it was real! Many listeners were in panic thinking that America was attacked by aliens.

Some people believe there is life in space. If so, Mars may be a likely place. We know that right now that the surface of Mars is now a cold, dry, lifeless desert. Yet, billions of years ago maybe there was a chance for life to start on Mars. Why? Because it is very likely there was water.

How can we know there was water on Mars? One line of evidences comes from some of the images taken with the satellites circling the planet where we see things that look a lot fans on Earth.

Alluvial fan in California, USA. Copyright © Marli Miller, University of Oregon.

What is a fan and why are fans important?

A fan is a landscape feature that looks like a cone. They are created by sediment deposits (dumps) from a source, usually a river. Take a handful of sand or sugar and let it flow out on a flat surface. You just produced your first fan. If it were a river that laid down the sand, the fan would be called alluvial fan (alluvial means the stuff has been dumped by running water). When a river runs into a lake or the sea, the water stops flowing and everything the river has carried along – boulders, gravel, sand, clay – is dumped into the standing water. This forms a fan that we call delta. Famous ones are the Rhône, Mississippi and Nile deltas.

To understand what's going on at the bottom of a river, have a look at this animation by MadKrow.

All these fans can tell us a lot about the water cycle here on Earth, and on other planets too. This is where it gets really interesting.

The Earth (left) and Mars compared for size.

Humans have looked for life on Mars for centuries – first through telescopes, then through spacecraft images, and now using surface rovers. Why does it matter?

No water no life

Water is an absolute must for even the most primitive life forms that we know of. The most recent Mars explorations proved that there is indeed (frozen) water on Mars (using the Gamma Ray Spectrometer, which looked for hydrogen in the upper few metres of the surface.) In fact, if its polar caps melted, the surface of Mars would be covered with eleven meters deep!

One of the first pieces of evidence of water on Mars on a Viking mission photo. Because the image does not show small details it was not clear if the river is running into or out of the crater. (Cabrol and Grin, 2000.)

For life to have a chance it needs a moist environment. And this environment needs to be steady for a long period of time, probably a few thousand years for the chemical reactions to take place. The question now becomes: did Mars ever have such an environment? Fans can help us understand this question.

In the late 1990’s, two scientists, Natalie Cabrol and Edmond Grin, made a catalogue of unusual features seen in some images taken from Mars. They identified places where things such as channels and shorelines were observed in impact craters. They discovered strange deposits in some of the impact craters and at the end of some of the valleys. They faced a big problem, however. The images were not detailed enough to reach any real conclusions about which way the water might flow or if it was even water at all.

Mars exploration 

1996 was the start of a new and exciting time in Mars exploration. Since then, 7 US and European missions have successfully arrived in Martian orbit. We now have millions and millions of detailed images of Mars. Its surface looks very familiar: apart from the many craters it has volcanoes, but also what seem to be dry rivers and lakes. Now what about these strange deposits found by Natalie Cabrol and Edmond Grin?

Fossil fans in Melas Chasma on Mars on one of the last images by Mars Global Surveyor. Photo: NASA/JPL/Malin Space Science Systems, http://www.msss.com/msss_images/2007/04/13/. Click on Photo for details.

We are now sure that fans form on other planets as well. They also come in different shapes and sizes. And on Mars, the difference between deltas and alluvial fans becomes very important. It tells us a lot about the water cycle on this little planet. At some point there had to be plenty of liquid water on Mars. Its atmosphere had to be warmer and thicker in those days. Of that we can be sure.  Regrettably we cannot tell if there ever was life on Mars, ..... yet.

But the study of these fans tells us that once (billions of years ago) there were rivers and lakes on Mars. It takes time to form rivers and lakes. Just like the creation of life. The next question then is: were the rivers and lakes around long enough to create possible life forms? Soon new rovers will go to Mars to conduct detailed chemistry experiments. Places were we know water flowed, like fans, are good places for them to land!

Till today, we cannot tell whether there was a steady and moist environment at the time. For example, we don’t know how long it takes for water to be sucked into the soil under the different atmospheric conditions that existed on Mars. Relatively short lasting waterballets are simply not good enough to create life. We also do not know the exact composition of Mars’ geological layers.

Mars is now completely dry. (NASA: artist impression.)

So, why don’t we just empty a bucket of water on Mars and see what happens? No use, I am afraid. Water instantly freezes and evaporates in the cold and dry atmosphere of Mars. You can compare this to the way ‘dry ice’ (frozen CO₂, -78.5 ºC) behaves on our planet (see: film).  Instead we must make laboratory experiments to understand how fans formed on Mars. So where to take it from here?

Experiments

In our lab we can try to produce the same things that we see on the Mars photos, and figure out how they may have formed. In the Eurotank at Utrecht University we let miniature rivers run into miniature meteorite craters. We change how much water flows into the crater and how much sediment it carries. So, we carefully control erosion, sediment transport and deposition (see animation explaining these terms). We can now look at the different results and compare them with the things we see on Mars. Now, we have a better idea of what exactly went on billions of years ago on Mars.

The film about my research in the Netherlands will show you how we did it:

Click the image to start the film.

Now it's your turn. You can start right here on Earth! A bit of sand and water will get you on your way. We know quite a lot about Mars’ surface. Try to create a Martian fan yourself.

Investigate how these features formed on Earth.

What can it tell you about the water cycle?

Find out how many clues about Mars’ history your own water cycle hides.

If you manage to create life yourself, do let us know!

Sources

Cabrol, N. A., E. A. Grin, and W. H. Pollard 2000. Possible frost mounds in ancient Martian lakebed. Icarus,145. 91-107.

About alluvial fans: Alluvial Fan, China http://asterweb.jpl.nasa.gov/gallery-detail.asp?name=fan

Erin's website at Virginia Tech http://www.geos.vt.edu/people/ekraal/

A short film of the experiments at YouTube  

About the Eurotank at Utrecht University:
http://www.geo.uu.nl/phpscripts/staffpages/personal/personal.php?id=Postm101

Martian crater records aftermath of Amazon-like flood, article in New Scientist  

Erin's article in Nature  

VPRO, Dutch television: Marswater stroomde kort maar hevig - Zandbakgeklieder verheldert Mars' natte verleden website and here is the link to the tv programme Noorderlicht Nieuws  (in Dutch)

Comments

Curator/ amateur-egyptian historian Chil Written by This e-mail address is being protected from spam bots, you need JavaScript enabled to view it on 2008-02-26 18:26:29 ABOUT posibility of other watery planets in any Solar stystem: NONE unles in closed tide formation with giant Planets( as TITAN or Europa, with ceacked iceflow surfaces.)    MARS in order to contain stable standing water should thus have orbited closer to the Sun, or, have more gravity thus more Volume !    MARS- HISTORY is well known I DO NOT MEAN, it's alluvial fan history but: ancient Historyfrom 1.000 bc tthis Planet was observed by egyptians and greek     ASTRONOMERS, who noted that it was in close Orbit afround the Sun and visisble without telescope just like the Moon today.    CONSEQUENTLY it had more tidal influence on Earth than the -standing alone-Moon today.    THEREFORE the Egyptians RECORDED annual TSUNAMIES caused by Moon and MARS in conjuction( such as the Biblical    FLOOD( which the Greeks named the CATACLYSM of DEUKALION) Who incidentally was also the Father of PANDORA.    ALAS Many if not ALL- Astrophycists regard the egyptian/greek records of MARS-orbit in 1.000-855 bc as pure romantic Fiction     which is a pity because ancient Astronomic RECORDS however incompled could tell a Lot about the Forming of MARS for the last 2 milleniums.    FOR-INSTANCE:  DEMOCRITUS( writing in 500 bc.) tells that the ancient Egyptians still could see green seasons on Mars and it's giant rivers before the Year 855 bc.    THUS if we are to believe the compilatiobns of DEMOCRITUS Mars rivers still flowed in 855 bc.    HE EVEN RECORDS what happened to the contrary: At the last TWO of the annual-MARS - MOON conjuctions, they came too close and bumped into eachother which caused    the MOON to lose Sattelites which as "MARUTS " fell into a well watered Arabian DESERT,    ON THAT occasion, MARS cracked and formed TWO new smaller Planets: Mars & Mercury.    EGYPTIANS renamed MARS Osiris and the MOON was SETH, Mercury became ( the younger=Golden-)HORUS whilst the former amalgamate -became  the ( now non-existing RED-HORUS.)     In GREECE the Planet MARS before 855 bc was still know as the WATER- PLANET : "POSEIDON ".    More in my ABSTRACT at the ( my: Atlantis-discovery )Heliotopos-Conference.net in ATHENS on Nov. 10-11 2008. dd Internetrecluse "Blue-Hue" now 26 Febr. 2008 TUD-Delft.

Written by sam on 2008-02-25 19:08:17 its possible that there is life on mars. my question is how many other planets might have life on mars

Written by This e-mail address is being protected from spam bots, you need JavaScript enabled to view it on 2008-02-21 11:29:02   This is one of the most interesting experiments I have ever seen!  Mars is exciting.

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